mark99, there doesn't seem to be so when I searched the PHP-related pages on vBulletin and on PHP.net.
Ramirez, if you have PHP and even if you don't have zlib, you're better off running the accelerator because 1) php grabs pages faster and 2) it's a lot less load on your server.
As always, WOL still DOES NOT work with UBB Accelerator so you have been warned.
qasic